InChI=1S/C19H20O8S/c1-12(11-20)2-6-15-17(22)8-14(9-18(15)23)4-3-13-5-7-16(21)19(10-13)27-28(24,25)26/h2-10,12,20-23H,11H2,1H3,(H,24,25,26)/b4-3+,6-2+